Compounding

Compounding consists of preparing plastic formulations by mixing and/or blending polymers and additives in a molten state, these blends are automatically dosed with fixed setpoints usually through feeders/hoppers.

Compounding is usually done by extrusion. The hopper feeds the begin of the screw which will gradually transport the resins towards the die. The screw itself is confined in a barrel that has different zones that can be heated according to the resins properties.

Co-kneaders and twin screws (co- and counter rotating) as well internal mixers are the most commonly used compounders in the plastic industry.

HAAKE™ MiniCTW Micro-Conical Twin Screw Compounder

The ThermoFisher™ HAAKE™ miniCTW (or mini-compounder) is very appropriate to compound and extrude small quantities. This conical double-screw compounder enables us to test a large spectrum of different materials and to screen a large number of processing conditions or product combinations in an affordable and quick manner. Ideal for tests with nanomaterials or engineered biopolymers.

The optional Force Feeder system enables a continuous material throughput. This screw-feeder is air-cooled to prevent clogging.

In addition to a continuous extrusion mode, the minicompounder allows a backflow mode through a recycle configuration, resulting in a optimised blend. The use of pellets involves that the material dosing is approached from a statistic distribution. However, this is solved by using powders or by partly mixing the blends beforehand.

The co-rotating and counter-rotating configurations guarantee an optimised blending. The heat regulation is limited to one single temperature for the entire barrel and cannot be divided into different zones.

The mini-compounder is computer assisted enabling the online follow-up and graphic display (in function of time) of temperature, screw speed and couple. It is also possible to add an event at a certain point of time.

Temperature can be set between ambient temperature and 300°C, with a heat output of 800W. The screw speed can be set between 10 to 360 rpm - max. couple of 5Nm.

Although it is possible to preset many parameters (temperature, screw speed and couple) it is not straightforward to upscale the process. However, by applying optimised process parameters, it is possible to produce blends with an extremely fine dispersion.

Yarn extrusion

The minicompounder is used for yarn extrusion pilot tests by means of the Force Feeder for a continuous material throughput or by means of the blackflow system for an optimal blend.

The extruded filament is aircooled over a conveyor belt. The preset speed determines the yarn thickness.

ISO - Plastic test samples

The HAAKE miniCTW can be connected to the Thermo Scientific™ HAAKE™ miniJET. This apparatus is used to produce small test samples of 0,9 - 1,3 g. The mechanical properties of these test samples (ISO-dimensions) are then tested.

The ENGEL 1350/250 HL is designed without tiebars, guaranteeing a large freedom in mould design and rapid mould switches.

Technical specifications of the ENGEL 1350/250 HL

Max. clamping force: 2500 kN

Max. open (at min. installation height): 850 mm

Min. installation height: 350 mm

Dimensions clamping platen: 1050 x 650 mm

Flange diameter: 160 mm

Max. ejector force: 82 kN

Max. ejection stroke: 200 mm

Srew diameter: 60 mm

L/D ratio: 20/1

Max. shot volume: 735 ccm

Max. Couple on screw: 1481 bar

Max. injection speed: 407 ccm/sec

Max. dosing speed: 43 m/min

Max. nozzle pressure: 110 kN

KraussMaffei 125 –700 C2

Technical specifications of the KraussMaffei 125 –700 C2

Max. clamping force: 1250 kN

Max. open (at min. installation heigth): 600 mm

Min. installation height: 300 mm

Dimensions clamping platen: 745 x 770 mm

Bar spacing: 470 x 470 mm

Flange diameter: 125 mm

Max. ejector force: 22 kN

Max. ejection stroke: 150 mm

Srew diameter: 50 mm

L/D ratio: 20/1

Max. shot volume: 377 ccm

Max. injection speed: 181 ccm/sec

Max. dosing speed: 40 m/min

Max. nozzle pressure: 84 kN

Compression ratio: 2.1 to 1

Surface modification

Some polymers contain apolar groups. Their surface is therefore low on energy and not easy to bond or wet. This results in poor adhesions of coating layers. To ensure proper bonding or coating a surface modification is necessary. This is done by oxidising the top layer and so introducing polar groups.

Corona treatment

A plastic film is passed over a metal roll, placed at approximately 1 to 2 mm underneath an electrode. An alternating current passes through the electrode at 20.000V. This leads to a continuous discharge to the plastic film that modifies the surface structure.

Atmospheric plasma

Plasma is a gas in which the gas molecules disintegrate into individual atoms, free radicals, electrons and photons. They bombard the plastic’s surface and lead to polar groups. In the case of atmospheric plasma, air is used instead of an inert gas.

Plasmatreat® Openair jet

Plasma technology is based on a simple physical principle. Matter changes its state when energy is supplied to it: solids becomes liquid, and liquids becomes gaseous. If even more energy is supplied to a gas, it is ionized and goes into the energy-rich plasma state, the fourth state of matter.

Method

A process gas such as air, nitrogen or mixed gases is guided through a jet in which a high voltage discharge turns it into Plasma.

This highly reactive plasma is electrical potential fire and will clean, activate or coat surfaces in order to create perfect adhesion or add functionalities (such as hydrophylic, Hydrophobic, anti corossion, ...)